Barcodes are widely used to provide fast and convenient identification of an item. Affixing a barcode to an item provides a machine-readable label which can contain either direct information about the item or serve as an index to a stored catalog or directory of items, which may contain as much information about each item as is desired. The use of barcodes is particularly prevalent in retailing. A specific brand or model of an item can be uniquely identified using a bar-coded identification number, with the identification number being quickly and easily read at the time of a transaction. Because the specific class of item can be identified, it is not necessary to place pricing information on the item. Instead, pricing information can be stored in a central computer, making it easy to change pricing for a particular brand or model without individually marking each item. Moreover, the identifying information contained in a barcode makes it easy to maintain records of inventory and to track and store sales information for an item.
It is often desirable to include supplemental information about particular items in a class of items, which are distinguished in some way from the class as a whole. In retailing, for example, it is often desirable, particularly in connection with perishable foods, to discount an individual item without discounting all other items of the same brand and type. For example, if a perishable item is approaching or has passed the end of its shelf life, it may be desired to discount the price of the item to encourage its immediate purchase. In barcode scanning systems of the prior art, this can be accomplished through manual intervention on the part of the operator. This requires that the operator recognize the item as one which has been marked down, typically through a human-readable label prominently affixed to the item. The operator must also know the markdown price and manually enter it, or must manually activate a markdown function on the scanner which will indicate to the central computer that the individual item has been marked down and instruct the computer to retrieve and apply the new markdown price. This is a labor-intensive operation, requiring that each item to be marked down be individually relabeled, and that the operator of the scanner intervene manually with each marked-down item. The operation is therefore costly and is subject to human error.
Alternatively, for each item of a particular type which is to be marked down, a new barcode label may be printed and affixed over the old barcode label. A single label for all product types, simply indicating that the item has been marked down, is insufficient, as the central computer will be instructed that the item has been marked down, but will not be informed of the identity of the item. The new barcode label should therefore contain information identifying the product type as well as an indication that the item has been marked down. This requires a different label for every product type, as well as the labor to affix a label to each item to be marked down. Moreover, in retailing such a barcode is nonstandard, as a standardized system of retail barcode labels exists, each identifying a specific item class, such as a particular brand and size of item. The use of a nonstandard barcode would give up the convenience of using the standard barcode, and would introduce increased complexity into the system, as the system would need to be adapted to accommodate the specialized barcodes used to contain both the primary and the supplemental information.